1. Field of the Invention
The present invention generally relates to an improved cellular cushioned material and to an improved pre-welded cellular cushioned material and a method for making the same in particular.
2. Discussion of the Related Art
Cellular cushioning material is used for packing and for the filling of empty volumes. U.S. patent application Ser. No. 09/758,544, publication Ser. No. 2002/0094393A1, U.S. Pat. No. 6,682,622 filed by Matarasso discloses a pre-welded cellular cushioning material and method, the method includes providing a pre-welded sheet to a user comprised of at least two layers of plastic pre-welded to have a plurality of diagonally oriented, inflatable sleeves extending substantially the entire width of said sheet, and a longitudinally extending air entry passage. According to Matarasso each of the inflatable sleeves has an opening for allowing entry of air from said air entry passage into the sleeve. The user inflates the cellular cushioning material using an air injecting pipe located in the center of the sheet inflated, the pipe is inserted into the mid section of the plastic sheet using a knife for cutting a passageway in the middle or side section of the inflatable plastic sheet.
According to Matarasso each of the sleeves is welded from all sides except for a small opening. Once air is injected into the diagonal sleeves a horizontal welding is applied to the plastic sheet. The horizontal welding is applied to the inflated plastic sheet at predetermined intervals. The welding is applied using horizontal bars. Each weld determines the production rate of the cellular cushioning material. Due to openings between the pre-welded sections entire areas juxtaposed to the air inlet pipe are not sealed from all of their sides causing a significant reduction in the efficiency of the partially inflated plastic sheet.
Reference is now made to FIG. 1 which shows a plastic sheet having a plurality of diagonally oriented, inflatable sleeves extending substantially the entire width of the shown sheet, known in the art. Once diagonal sleeves 100, 101, 102 are air filled, horizontal weld 104 is made using horizontal welding bars, thus creating non-inflated area 108. Like non-inflated areas are located throughout the length of the air filling section of the plastic sheet. The longer the distance between horizontal welds 104, 106 the larger the non-inflated section that is created within the plastic sheet.
It is therefore an object of the present invention to provide a pre-welded cellular cushioning material having a minimal non-inflated section.
It is also an object of the present invention to provide an additional longitudinal weld during the process of welding thus minimizing the non-inflated section during the production of the inflated cellular cushioning material.